Method and system for the transmission of radiant energy



E. L. CHAFFEE.

METHOD AND SYSTEM FOR THE TRANSMISSION OF RADIANT ENERGY Fil d April 251918 5 Sheets-Sheet i PLATE CURRENT 0 \emu VOLTAGE PLATE CURRENTWITNESS: 0 uvvm r01? 4/ I I I .92

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E. L. CHAFFEE METHOD AND SYSTEM FOR THE TRANSMISSION OF RADIANT ENERGYFiled April 25 18 5 Sheets-Shae? 5 HIS Arm/mu Nov. 3, 1925' 1 1,560,206E.L.CHAFFEE METHOD AND SYSTEM FOR THE TRANSMISSION OF RADIANT ENERGYFiied April 25. 1918 5 Sheets-Sheet 4 iwmsss;

I INVENTOR ms Ana/Mi Nov. 3, 1925 1,560,206

E. L. CHAFFEE METHOD AND SYSTEM FOR THE TRANSMISSION' OF RADIANT ENERGYFiled April 25. 1918 5y Sheets-Sheet 5 PLATE CURRENT O vours 0N PLATECURRENT WITNESS." IIVVE/VTOR H/S ATTORNEY Patented Nov. 3, 1925.

- UNITED STATES PATENT, OFFICE.

EMORY LEON CHAIFEE, or BELMONT, MASSACHUSETTS, ASsIeNon 'ro JOHN HAYSHAMMOND, JR, or oLoUoEs'rEn, MASSACHUSETTS;

METHOD AND SYSTEM. FOR THE TRANSMISSION OF RADIANT ENERG Y.

A pplicationflled April 25, 1918. Serial No. 230,722.

To all whom it may concern Be it known that I, EMORY LEON CHAF FEE, acitizen of the United States, and a resident of Belmont, in the countyof Middlesex and State of Massachusetts, have invented certain new anduseful Improvements in Methods and Systems for the Transmission ofRadiant Energy, of which the following is a specification.

Some of the objects of this invention are to provide in a receivingsystem for radiant energy means for reducing the disturbing effects ofatmospheric strays orstatic, or interference from high potential highlydamped wave trains, or other disturbing effects while receiving a radiosignal, without seriously reducing the intensity of the received Signal;to provide in a receiving sys tem for radiant energy, means forprotecting an oscillation detector from interfering high potentialeffects; and to provide other improvements such as will appearhereinafter.

In the accompanying drawings, Fig. 1 is a diagrammatic representation ofa receiving system constructed in accordance with this invention; Figs.2 to 8 are diagrams explanatory of the operation of the system shown inF ig. 1; Fig. 9 is a diagrammatic representation of a modified form of aportion of the system shown in Fig. 1; Fig. 10 is a diagram explanatoryof the operation of the modified system shown in Fig. 9; Fig. 11 is afurther modified form of a portion of the system shown in Fig. 1; andFigs. 12 and 13 are diagrams explanatory of the operation of the systemshown in Fig. 11.

Referring to the drawings and particw larly' to Fig. 1, one form ofreceiving system constructed in accordance with this invention comprisesan open aerial circuit 25, including an antenna 26 and an inductance 27,through which the antenna 26 is grounded as at 28. The inductance 27forms the primary of a transformer 30, which includes a coil orinductance 31, which is in a closed oscillatory circuit 32, including avariable condenser 33. This closed circuit 32 is preferably' tuned tothe frequency of the open aerial circuit 25 and is arranged to actthrough a stoppage condenser 34 to control any well-known or suitableoscillation detector, for instance, a vacuum'tube detector 35 ofwell-known construction and comprismg an evacuated glass bulb 36 whichcontains a filament 37, a grid or potential gradient changing means 38,and a plate ortermmal 39. The filament 37 is arranged to be heated by abattery 40, acting through a variable resistance or rheostat 41, and thedetector 35 is arranged to control a circuit 45,

which is energized by a battery 46, andwhich is arranged to energize atelephonic receiver f17, or any other suitable signalling or receivingdevice.

For protecting the detector 35 from the disturbing effects ofatmospheric strays or static, or interference from high potential highlydamped wave including a primary valve 50 and a corretrains or other unde.sirable disturblng effects, this invention pro- 34 or 33, or thehereinbefore dewill produce substansponding secondary valve 51, and aprimary valve 52 and a corresponding secondary valve 53. These valvesmay be of any suitable construction, but in the form shown each of thesevalves includes a glass bulb or suitable container 55, which isevacuated and which contains a filament 56, a grid or potential gradientchanging means 57, and a terminal or plate 58. Each filament 56 isarranged to be heated by a bat tery 6O acting through a variableresistance 61. Across the terminals of each of the heating batteries 60of the two primary valves 50 and 52 is a resistance 65. These tworesistances 65 are rovided respectively with two sliding or adiustablecontacts 66, which are connected respectively by two conductors 67 totwo spaced terminals 68 and 69. The terminals 68 and 69 are joinedthrough a resistance 70 and are connected retwo high voltage batteries73 to the two plates 58 of. the two primary valves 50 and 52. Betweeneach pair of valves 50 and 51, and 52 and 53, is a battery 7 5,0ne poleof which is connected by a conductor 76' 85 and 86- to the oppositesides of the variable condenser 33. Instead of being connected to theopposite sides of the variable condenser 33, these two conductors 85 and86 may be connected to the opposite sides of the stoppage condenser 34or to the opposite sides or ends of the, inductance 27, or across anyother suitable part or element of the circuits which control theoscillation detector 35.- I

It is evident from the foregoing that the primary valve 50 and thecorresponding secondary valve 51 of one of the hereinbefore describedtwo pairs of valves are connected in parallel betwen the two terminals68 and 69 so that these two valves act conjointly to permit a negativecurrent to pass from the terminal 68 towards the terminal 69 and toprevent a positive current from passing through the valves from theterminal 68 towards the terminal 69; and it is also evident that theother primary valve 52 and the corresponding secondary valve 53 arearranged to permit a positive current to pass from the terminal 68towards the terminal 69 and to prevent a negative current from passingfrom the terminal 68 towards the terminal 69.

In the operation of the form of this invention shown in Fig. 1, each ofthe primary valves and 52 is preferably, operated at a low heat so as toproduce the well-known saturation current. The variable contact 66 ofeach primary valve 50 and 52 is preterably so adjusted together with thecorrespending battery 73 that the characteristic plate current-gridvoltage curve of each of the primary valves 50 and 52 is substantiallyas shown in Fig. 2 by the full curved line 90, which is plotted withrespect to the two axes 91 and 92, which intersect at rightangles andalong which are measured respectively the plate current and volts on thegrid. The filament 56 of each of the two secondary valves 51 and 53 isoperated preferably although not necessarily at a higher temperaturethan the filament 56 of the. corresponding primary valve 50 or 52, andthe corresponding battery 75 is preferably so connected to thecorresponding primary valve 50 or 52, as shownin Fig. 1, the grid 57 ofthe primary valve 50.or 52 is conneotedto such a point in thecorresponding battery 75- by means of the tap 81 that the voltagebetween the grid 57 and the filament 56 of the primary valve 50 or 52 ispractically zero. If now the voltage of the grid 57 of either secondaryvalve 51 or 53 should be increased positively, the current through thecorresponding battery 75 and the corresponding resistance 77 .would beincreased accordingly, giving. an increased drop in the resistance 77.This increased drop would act to make the grid 57 of the correspondingprimary valve 50 or 52 negative with respect to the correspondingfilament 56, and the plate current of the corresponding primary valve 59or 52 would be correspondingly decreased.

The combined characteristic curve representing the operation of eitherpair of valves 50 and 51, or 52 and 53, when connected without theresistance 7 0 between the two terminals 68 and 69 is shown inFig. 4 bythe full curved line 100. It is to be noted that this curved line 100 isa curve of plate current plotted against grid voltage. The slope of thecurve 100 in Fig. 4 may be made much steeper than the slope of thehereinbefore described curve 90 in Fig. 2 by a proper adjustment of thebattery 75 and the resistance 77. For instance, the total drop incurrent may take place in less than one tenth volt change in potential.The curve 100 of Fig. 4 may be moved horizontally towards the plus orminus volts by means of an adjustment of the corresponding contact 66 onthe corresponding resistance 65. The

secondary valve 51 and 53 serve to reverse the curve 90 of Fig; 2 andsteepen it if de sired.

If both pairs of valves 50, 51 and 52, 53 be operated simultaneously,the operation of the two pairs of valves would be indicateddiagrammatically and approximately by the two full curved lines and 106respectively as shown in Fig. 5, and these two curved lines 105 and 106combined would give approximately the characteristic full curved line110 shown in Fig. 6.

If now the resistance 70 be connected between the terminals 68 and 69,the resulting characteristic curve of the operation of the J two pairsof valves may be obtained by adcated in Fig. 7 by the dotted curved line115,-the strai ht l1ne representing the characteristic of t e resistance70 beingindicated by the straight dotted line 116, and the re sultantcurve being indicated by the full curved line 120. I

From anexamination of the resultant characteristic curve 120 in Fig. 7,it is evident that in the operation of this system a fluctuation ofvoltage of, for instance, one tenth of a volt on either side ofthe zeropoint or origin, between the two terminals bend in the curve 120,

68 and 69 would produce no appreciable flow of current through theauxiliar For such voltage fluctuation, t system 49 has very'highequivalent resistance, and since the auxiliary system-49 is connectedacross the condenser 34 or 33 or across an inductance 27, this auxiliarysystem 49 in no way interferes with the reception of a signal of radiantenergy the fluctuation of voltage of which falls below the sharp bend oft e curve 120. If, however, the voltage is slightly greater than say onetenth of a volt, which corresponds to points on the rising part of thecurve just past the sharp bend, then a relatively large current willflow through the auxiliary system 49, and the equivalent resistance ofthe aux iliary system 49 will fall to a few thousand ohms, or even to afew hundred ohms.

The auxiliary system 49 therefore acts, when connected across thestoppage condenser 34 or the variable condenser 33 or the inductance 27,as a by-pass for all oscillations producing a voltage fluctuationgreater than the small fluctuat on up to the sharp and, as a by-pass,acts to cut off the tops of intense voltage waves. Consequently, thevoltage variation on the grid 38 of the receiving detector 35 of Fig. 1will not be appreciably greater under the influence of intense signalsthan under the signals.

A modified form of characteristic curve of the auxiliary system 49 isshown approximately by the full curved line of Fig. 8. This curve 125shows a negative slope for the portion of the curve passing through theorigin or zero. This negative slope represents a negative resistancewhich means that for fluctuations in potential which are confined to thenegative slope of the curve, the auxiliary system 49 furnishes energy'tostill further increase the voltage fluctuation. Such a characteristiccurve implies an amplification of a weak signal, but the reduction ofthe strong disturbances is effected in the same manner as hereinbeforedescribed in connection'with the curve 120 .in Fig. 7.

In Fig. 9 is shown a modified form of protective auxiliary systemconstructed in accordance with this invention. In this system 49. eauxiliary influence of relatively weak battery 137. The characteristiccurve showing the operation of the valves. 50 ,and 5.1 of this modifiedauxiliary system 130 is shown approximately by the dotted line 140 inFig. 10, which is approximately the same as the curve 100 in Fig. 4. Thecharacteristic curve of the resistance and the otentiometer' 136 isshown approximately y the dotted line 141 in Fig. 10. The resultantcurve formedby combining the two curves 140, 141 is shown approximatelyby the full curved line 142 of Fig. 10. If the slope of the curve besuitably increased and then combined with the curve 141 of theresistance 135 and potentiometer 136. the resultant curve wouldapproximate the form shown by the line 125 in Fig. 8.

Another modified formg149 of the auxiliary protective system constructedin accordance with this invention is shown in Fig. 11. In this modifiedform 149, the construction is the same as in the form hereinbeforedescribed and shown in Fig. 1, except that instead of having the twoterminals 68 and 69 connected by the hereinbefore described resistance70, this resistance is omitted and in place thereof two oppositelyarranged thermionic valves 150 and 151 are substituted. These valves areconstructed as hereinbefore described, and

the filament 56 of each of thesevalves is arranged to be heated by acorresponding battery 152, across the polesof which is a potentiometer153. The two filaments of the two valves 150, 151 are connectedrespectively through two corresponding batteries 155, 156 to thecorresponding grids 57. thus giving the grids a positive potential. Thepotentiometer 1530f one. 150, of these valves is connected through thehereinbefore described conductor 67 to the hereinbefore describedterminal 68, while the potentiometer 153 of the other 'valve 151 isconnected through, the hereinbefore described conductor 67 to the otherhereinbefore described terminal 69. The two batteries 155 and 156 areprovided respectively with two adjustable taps 160 and 161 whicharelconnected respectively by two conductors 162 and 163 to the twoplates or terminals 58 of the hereinbefore described primary valves 52and 50 respectively, the. hereinbefore .described batteries 73 beingomitted and the added batteries 155 and 156 being thus arranged toperform not only the functions of maintaining the corresponding grids 57with a positive potential, but also performing the function of theomitted batteries 73.

In the operation of the modified form 149 of the auxiliary protectivesystem shown in Fig. 11, the terminals 68 and 69 may be connected ashereinbefore described across the stoppage condenser 34, or across thevariable condenser 33 or across inductance 27 of Fig. 1 by thehereinbefore described conductors 85 and 86.

In this modified form, shown in Fig. 11, the characteristic, platecurrent-plate volt-- age curve showing the operation of either one ofthe valves 150 or 151, when connected as shown in Fig. 11 and as justdescribed, would be represented approximately by the full curved line170 of Fig. 12. This curve 170 may be moved horizontally by a suitableadjustment of the corresponding potentiometer 153. If both valves 151and 152 be operated simultaneousl their combined curves may beapproximate y any one of the curves 175, 176, 177 shown in Fig. 13, orother similar curves, according to the adjustments of the potentiometer153'. If one of these latter curves, which takes the place of thestraight line resistance curve 116 in Fig. 7,

' be combined with the curves for the hereinbefore described primaryvalves and 52 and secondary valves 51 and 53, the resultant curve wouldapproximate either the curve 120 in Fig. 7' or the curve 125 in Fig. 8

It is thought to be evident from -the-'foregoing that when any one ofthe several forms of auxiliary systems shown? in Figs. 1, 9 and 11 andhereinbefore described, is connected across the stoppage condenser, 34,or the variable condenser 33, or the inductance 27, if the potential ofthe 'receiv-' ing system at the points of connection should be increasedat any time either positively or negatively beyond a predeterminedlimit, above the limit ordinarily reached as a result of the receptionof an ordinary wireless message, then the auxiliary system 49, 130 or149, which would be normally inoperative up to a point where suchlimited potential had been passed. would instantaneously be renderedoperative at the moment of reaching such peak or limit of potential topermit a sudden rush of current and a consequent leak of potentialaround the condenser, conductor or other part across which the auxiliarysystem might be connected to limit the variation in potential of suchpart and consequently to limit the produced oscillations in such part.When high voltage oscillations are being received by the open aerialcircuit 25. if the amplitude of such oscillations should he suddenlyincreased be' yond the limits predetermined by the auxiliary system 49,130 or 149, then the auxiliary system would act as hereinbeforedescribed to protect the oscillation detector 35 and to prevent anyvariation in voltage therein beyond the limits predetermined by theauxiliary system, while the excess of voltage would be renderedinefi'ective by the auxiliary system to interfere with the operation ofthe detector 35. In case of the reception by the open aerial circuit 25of radiant oscillations havin a variation of amplitude beyond the limitsprescribed by the auxiliary system, the two sides of the responding sideonly of the auxiliary system 49, 130 or 149 would be thrown intooperation to minimize or overcome the effect of any excess amplitude orvoltage.

While only a few of the many forms have been shown in which thisinvention may be embodied, it is to be understood that the invention isnot limited to any specific construction or arrangement but might beapplied in various systems without departing from the spirit of theinvention-or the scope of the appended claims. f a

Having thus fully describedthis invention, I claim:

1. In a radio receiving system, the combination with an oscillation'detector, of means to protect said detector from high potential eflectsof a given polarity, comprising a primary and: a secondary thermionicvalve connectediii-parallel to the detector circuit.

2. In a radio receiving system, the com bination with an oscillationdetector, of means to protect the same from high potential efiects ofeither polarity, comprising two pairs of thermionic valves connected inparallel and in opposition to each other across two terminals of thedetector circuit.

3. In a radio receiving system, the combination with an oscillationdetector. of means includinga primary and a secondary thermionic valvearranged to protect said detector from high potential effects of a givenpolarity, said valves being so arranged that the operation of one' ofsaid valves is modified by the operation of the other of said valv 5 4.In a radio receiving system, the combination with an oscillationdetector, of

means including two pairs of thermionic valves arranged to protectsaiddetector from high potential efiects of either polarity, said tam -means electrically connecting the grid 0f" given polarity, each of saidvalves comprismg a container, a terminal, a grid, and ionizing meansarranged in said container.

6. In a radio receiving s stem, the combination with an oscillationetector, of. means including a pluralit of cooperating thermionic valvesarrange to protect said detector from high otential eifects of eitherpolarity, each of said valves comprising a coner, a terminal, a grid,andionizing means arranged in said container.

7. In a radio receivin system, .the combination with an oscil ationdetector, of means including a pluralit of cooperatin thermionic valvesarranged toprotect said detector from high' potential efiects of a givenpolarity, each of said valves comprising a container, and a terminal, agrid,and ionizing means arranged in sa d container, and meanselectrically connecting the grid of one of saidvalves with the terminalof another of said valves.

8. In a radio receiving 5 stem, the-comb nation with an oscillationdetector, of, means including a plurality offcooperating thermionicvalves arranged to protect said detector from high potential effects ofeither each of said valves comprising. a

polarity, container,

and a terminal, a grid, and ionizing means arranged in said container,and

one of said valves with other of said valves. I

9. In a radio receiving system, the combination with an oscillationdetector, of means including a plurality of cooperating thermionicvalves arranged to protect said detector from high polarity, container,and a terminal, a grid, and ionizing means arranged in said container,and means including a source of electric energy electrically connectingthe grid of one of said valves with the'terminal of another of saidvalves.

10. In a radio receiving system, the combination with an oscillationdetector, of means including a plurality of cooperating thermionicvalves arranged to protect said detector from high potential effects ofeither polarity, each of said valves comprising a container, and aterminal, a grid, and ionizing means arranged in said container, andmeans including a source of electric energy electrically connecting thegrid of one of said valves with the terminal of anthe terminal flit-gallother of said valves.

11. In a radio receiving system, the combination with an oscillatoryelement, of means for limiting the amplitude of oscillation of saidelement, including a plural-' ity of pairs of thermionic valvesconnected in parallel across said element, each valve comprising aterminal, a grid, and ionlzmg means.

.element, each of said valves includin potential effects of a given eachof said valves comprising a- 12. In a radio receiving system, thecombination with an oscillatory element, of means for limiting theamplitude of oscillation of said-element, includin a plurality ofthermionic valves connectef across said a container, and a terminal, agrid and ionizing means arranged in said container.

In a radio receiving system,the. combination with an oscillatoryelement, of means for limiting the am litude of oscillation of saidelement, inc uding a plurality of thermionic valves connected acrosssaid element, each of said valve including a container. and a terminal,a grid, and ionizing means arranged in said container, and meanselectrically connecting the id ofone of said valves to the terminal otthe other of said valves.

14. In a radio receiving system, the combination with an oscillatoryelement, of

means including a plurality of devices connected across said element tolimit the amplitude of oscillation of said element, a plurality of saiddevices being arranged to permit the flow of an electric currentinagiven direction across-said element nda plurality of said devices beingarr the flow of electric current H site direction across said; e ment.

ged to permit "in an oppo- 15. In a radio 'receiving system, a combi- Ination with an oscillation detector, of means including a plurality ofcooperating thermionic valves arranged to protect said detector fromelectrical eii'ects having a maximum of potential beyond thepredetermined potential and of a given polarity, and means including aplurality of cooperating thermionic valves arranged to protect saiddetector from electrical effects having a maxi" mum of potential beyondthe given potential and of-a polarity opposite to said firstmentionedpolarity.

16. In a system for minimizing high potential charges induced in areceivin systerm for radio signalling, a plurality o thermionicvalves,each valve lncluding a grid and a plate and said valves beingcooperatively connected so as to mutually influence their respectivep-late current and grid volteach valve lncluding a grid 7 agecharacteristics in such manner as to proeach valve comprising ionizingchanging means between the same, and said eratively connected theretovalves being soconnected as to mutually in- .fluence theirrespective'efi'ective resistances,

as to produce a critical leak for potential of over a predeterminedvoltage and of either polarity. p

19. In an electrical system, a combination with a wave responsive deviceof means opior protecting said device from excessive potential efiects,comprising two three-electrode thermion c valves connected in paralleland in opposltion. I 1

20. In an electrical system, a combination with a thermionic waveresponsive device, of means operatively connected thereto for protectingsaid device from excessive potential effects, comprising twothree-electrode thermionic valves connected in parallel'and inopposition.

21. In an electrical system, a combination with an electrical device, ofmeans operatively connected thereto for protecting said device fromexcessive potential eflects, comprising two three-electrode thermionicvalves connected in parallel and in opppsitlon.

22. In a ra io receiving system, a detector, an impedance electrica yconnected with the input sideof the detector and means for protectingthe detector from undesired potentials, comprising a three-electrodether-' mionic valve having its plate-and filament connected acrosspoints on o posite sides of 1 said impedance and a secon three-electrodevalve having its' grid connected with the plate-filament circuit of thefirst-mentioned valve and having its own late-filament circuitconductively connecte with the-grid of the first-mentioned valve. w v

23. In a radio receiving system a detector, an impedance electricallyconnected with the input side of the detector and means for protectingthe. detector from undesired potentials,.comprisin a pair of circuitarrangementsconnecte to and oppositely arranged with respect to pointson opposite sides of said impedance, each of said circuit arrangementscomprising a three-electrode valve and means for automatically varyingthe charge on the grid of said valve under the control of potentialsinduced in the system from the ether.

24. In a radio receiving system, a detector, an impedance electricallyconnected with the input side of the detector and means for protectingthe detector from undesired potentials, comprising a second impedanceconnected across points on opposite sides of said first-mentionedimpedance, a pair of circuit arrangements connected in parallel withsaid second -mentioned impedance and oppositely arranged with respectthereto, each of said circuit. arrangements com rising a threeelectrodevalve and means m automatically varying the charge on-the grid of saidvalve under the control of potentials induced in the system from theether. 1

This specification signed April A. D. 1918.

EMORY LEON CHAFFEE.

this 22nd da of

